But he has pleaded not guilty to murder, arguing his schizophrenia left him unable to control himself.

"I think this young man has been inconsistent in his accounts of many, many things about the alleged offences," psychiatrist Pamela van de Hoef told McEwan's trial in the Brisbane Supreme Court on Monday.

"So it's really hard to know where the truth lies."

McEwan claims he was possessed by a demon named Jazzy when he repeatedly punched, kicked and strangled Ms Ban, 22, near her Roma St unit.

He then dragged her to nearby Wickham Park and dumped her under a tree where she drowned in her own blood after suffering extensive head injuries.